Fanless Power Supply PC Build Guide

To start things off, we put the system on full load and tested to see which intake fan position gave better results, and whether it was worth the extra noise to use both fans.

System Measurements: CPU + GPU Load

Intake Fans

Top

Bottom

Both

Temps

CPU

65°C

66°C

64°C

PCH

42°C

36°C

35°C

SSD

32°C

38°C

31°C

HDD

37°C

43°C

38°C

GPU

78°C

77°C

75°C

GPU VRM

84°C

83°C

80°C

System Power (AC)

280W

278W

277W

Noise Level @1m

17 dBA

17 dBA

17~18 dBA

Ambient temperature: 24°C.
Internal PSU temperature: 52~53°C.

The CPU and GPU temperature were hardly affected by the position of the fan. The bottom positioned favored the board's PCH chip to the tune of 6°C, while the upper fan provided a 6°C boost in HDD and SSD cooling (both drives sit directly in front of it). The two fans combined brought us the best of both worlds and also reduced the GPU and GPU VRM temperature by 2~3°C. As the fans we employed ran at only 500 RPM, the noise increase from the second fan was about half a decibel, making it a no-brainer to double up.

The X-400 power supply itself remained fairly cool on heavy load. Scanning the interior of the power supply with an IR thermometer showed that the hottest points were under 55°C.

System Measurements

Test State

Idle

H.264 Playback

CPU Load

CPU + GPU Load

Temps

CPU

38°C

39°C

58°C

64°C

PCH

30°C

31°C

33°C

35°C

SSD

27°C

28°C

30°C

31°C

HDD

34°C

34°C

36°C

38°C

GPU

35°C

45°C

38°C

75°C

GPU VRM

34°C

38°C

39°C

80°C

System Power (AC)

75W

104W

129W

277W

Noise Level @1m

17 dBA

17~18 dBA

Ambient temperature: 24°C.

When sitting idle and playing video, our system stayed very cool with the CPU temperature staying under 40°C. The CPU fan spun ~100 RPM lower than at load, reducing the noise level slightly to 17 [email protected] The efficiency of the i5-2500K is noticeable in our load tests. Stressing the CPU alone raised power consumption by a modest 54W  adding a GPU load on top of that required an extra 148W on top. Sucking down 277W, the X-400 is about 91% efficient, making the total power output 252W, approximately 63% of the power supply's rating so there was some headroom for more powerful hardware still.

Our HD 3300 IGP test system measured 18~19 [email protected] on load with the stock fans at 7V and CPU fan at 9V.

So how does did this build sound? Well at 17~18 [email protected], the volume of the system was quite low, and what was audible was very smooth, sounding like a pleasantly gentle 'whoosh.' This isn't really a surprise as each component was selected for superb acoustics. We used smooth sounding fans, the quietest hard drive on the market (suspended for good measure), a completely silent SSD, and a case with thick construction and dampened side panels.